Instrumentos fáciles de construir en casa

Didgeridoo de pvc
http://www.ensaimadamalabar.com/didge.htm
Un tubo de PVC de 1,30 metros y diametro de 5,8 centimetros aproximadamente.
Cinco o seis velas.
Papel de lija.
Pintura y pincel, o bien la tan socorrida cinta aislante.

Otro didgeridoo de pvc
http://www.didjshop.com/shop1/make_your_own_didgeridoo_es.html
tubo de PVC de cualquier comercio, con un diámetro interior de 40 mm. Que os lo corten o lo cortáis vosotros mismos; con una longitud exacta de 104 cm obtendréis un Mi, con 118cm tendréis un Re o con 132 cm un Do. Estas son las mejores notas para aprender. Pasar papel de lija por los extremos del tubo.
Consigue un pedazo de cera de abeja de algún apicultor o de algún comercio. Déjala al sol dentro de un vaso o jarra por una media hora (si tienes sol) o ponla en el microondas 10 segundos o al horno muy suave (~50-60°C).
Cuando la cera esté blanda y manejable haz como un fideo de 5 a 10 mm de grosor. Colócalo en el extremo del didge haciendo un aro y presiónalo, suavizando el interior y juntándolo bien con la madera. Trabaja la cera hasta conseguir un agujero de aprox. 35 mm. Puede ser ligeramente ovalado, pero sobretodo debe estar bien liso, sin prominencias ni huecos. Cuanto más redondo sea el agujero, más fácil será conseguir un buen sellado con la boca.

Didgeridoo de cartón
http://www.ensaimadamalabar.com/didgecart.htm
Un tubo de cartón de 1,30 metros y diametro de 5,8 milimetros.
Cinco o seis velas.
Pintura, barniz y pincel.

http://www.didjshop.com/physicsDidj.html

Xilófono
http://www.ensaimadamalabar.com/tubofono.htm
Un trozo de tronco de pita (38 cm). Sustituible por cualquier otro tipo de soporte.
Hilo de pescar.
Tubo de aluminio de 10 mm.
Tachuelas.
Nota Cm
Sol 5   29.84
La 6    28.19
Si 7     26.51
Do 1   25.72
Re 2   24.29
Mi 3    23.02
Fa 4    22.22
Sol 5   20.88
La 6   19.84
Si 7    18.41
Do 1  17.94
Re 2    16.83
Mi 3    15.80

Palo de lluvia
http://www.ensaimadamalabar.com/palolluvia.htm
Lentejas, semillas o pasta de trigo pequeña..
Palos de pincho, o clavos largos.
Un tubo de cartón.
Cinta aislante y esparadrapo (este es opcional).
Cartulina.

Tubo de truenos
http://www.ensaimadamalabar.com/tubotruenos.htm
Un muelle de alambre fino (resorte) y de unos 32 cm ( en ferreterias) .
Un tubo de PVC o cartón, de 110 mm y unos 10 cm de largo.
Papel de acetato.
cinta de embalar.
Cinta aislante para decoración.

Calimba
http://www.ensaimadamalabar.com/calimba.htm
Una caja metalica de bombones o similar.
Horquillas para el pelo.
Un trozo de chapa de madera.
Un trozo de listón de madera.
Unos tacos de madera (no estan en la foto).
Tornillos y cinta de electricista.

Tambor con bidón
http://www.ensaimadamalabar.com/tambor2.htm
Un bidón de pintura o similar.
Cinta de embalar.
Una radiografia.
Correa de persiana o similar.

Tambor con maceta
http://www.ensaimadamalabar.com/tambor.htm
Un maceta de plástico o de barro.
Papel vegetal (en papelerias) .
Cola blanca de carpintero y pincel.
Cinta de embalar y cinta aislante.
Papel para decorar.

Caleidoscopio
http://www.ensaimadamalabar.com/caleido.htm
Caja de CD .
Trozos de cristal de varios colores.
Un tubo de esos de medicamentos o vitaminas.
Cinta aislante .
Papel acetato y una bolsa de plástico.

INSTRUCCIONES EN INGLÉS PARA AVERIGUAR LA MEDIDA EXACTA SEGÚN LA NOTA O HERTZIOS QUE QUIERAS

http://www.didjshop.com/physicsDidj.html
Physics of the didgeridoo

On this page we will explore some of the physics of the didgeridoo and answer these questions:
  1. How long do I have to cut a (PVC) pipe to get a certain musical key?
  2. Which musical key will I get if I play on a pipe of a certain length.
This page is written using some material kindly supplied by Wolfgang Droescher (click here for Wolfgang’s original article).
First of all lets be clear no amount of physics will be able to describe a termite hollowed didgeridoo. Termite hollowed didgeridoos have a very irregular inner surface unique to each didgeridoo which do give many a genuine didgeridoo very interesting sound characteristics, but make it far too complicated to describe physically.
So for the purpose of this page we need to reduce a didgeridoo to a perfect pipe. Consequently this page is really about the physics of a PVC didgeridoo or any other didgeridoo as long as the inside diameter is exactly the same for the whole length of the didgeridoo.
Next lets have a look at some basic music theory:
  • Each musical note is defined by it’s frequency.
  • International tuning in music is based on middle A with a frequency of exactly 440 Hz (Hertz)
  • On a standard scale we have 12 notes in a full octave: c, c#, d, d#, e, f, f#, g, g#, a, a#, b, (c)
  • Due to the nature of sound waves the increase of frequency between two steps is not linear, but logarithmical. In plain words: the change of frequency cannot be described as “frequency of c plus increase factor equals frequency of c#”, but as “frequency of c multiplied by increase factor equals frequency of c#”
  • The frequency doubles on every octave, i.e. a’ = 440 Hz, a” = 880 Hz
  • Resulting from the two latter points we have an increase factor of the 12th root of 2 between any two musical keys (12 steps make 2 times the basic frequency) = 1.05946
Now that we have covered a bit of basic music theory lets see what actually influences f– the frequency a given pipe resonates at:
  • c – The speed of sound, which is 344 m/s in dry air at a temperature of 20° C (or 355 m/s in dry air of +40° C)
  • l – The length of the pipe
Note: The diameter of the pipe is not important at all for this basic calculation; a bigger diameter only makes the pipe sound louder as it gives a higher amplitude.
Which leads us finally to the physics formula determining the frequency a certain didgeridoo resonates at (as long as it is a perfect pipe):
  • f = c / 4l (Reads: The frequency (f) equals the speed of sound (c) divided by four times the length (l) of the open pipe)
  • Or, the other way round: l = c / 4f (The length (l) equals the speed of sound (c) divided by four times the frequency (f) )
Using this formula we have prepared this table that gives you both the frequency of a particular key as well as the length of a PVC didgeridoo in that key.


Let’s say you want to build a PVC didge with a musical key of C (as described on How to make a didge for less than 10$).

We need (apart from the hardware) the formula from above, the frequency table on left – and a calculator.
l = c / 4f = 344 / (4 x 65.40) = 344 / 261.63 = 1.315 m
That’s it!
The other way round: Let’s assume you found a wonderful hollowed branch (which is a perfect pipe) of roughly one meter in length out in your backyard and you are wondering which musical key this “didge” would make. After smoothing the edges a bit you end up with exactly 1.05 m. Take out your calculator and start off:
f = c / 4l = 344 / (4 x 1.05) = 344 / 4.2 = 81.90 Hz
This is pretty close to E (82.41Hz), so now you have a rough idea which key you can make out of it. Use the formula above to get the exact length for E (1.04 m) then cut off some more millimetres – done! Or simply leave your new didge as is, it’s close enough anyway.
As we stated earlier our calculations are based on the speed of sound in dry air at 20° C. So what happens if it gets hotter or colder, or wetter?
We will ignore humidity here as there is no easy formula to account for it and the speed of sound in air depends mostly on temperature; it can be calculated with this small formula:
c = 331.6 + 0.6 x t
with c = speed of sound in m/s
and t = air temperature in °C
Examples:
at 0° C you get c = 331.6 + 0.6 x 0 = 331.6 m/s
at 10° C you get c = 331.6 + 0.6 x 10 = 337.6 m/s
at 20° C you get c = 331.6 + 0.6 x 20 = 343.6 m/s
at 30° C you get c = 331.6 + 0.6 x 30 = 349.6 m/s
at 40° C you get c = 331.6 + 0.6 x 40 = 355.6 m/s
This means that the frequency of a 1.32cm long didgeridoo will be about 3.4% higher if the temperature is 40° C, which is halfway between C and C#.
As you can see extreme temperature changes will change the key of your didj, but a few degrees warmer or colder than 20° C do not matter much. Wolfgang also reminded me that we are talking about the temperature of the air going through the didj which is your breath. And that does not change that much.
Keep on didjing…

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Acerca de sonopuntura.com
Investigación sobre sonido y vibraciones en la salud

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